1. Field of the Invention
The present invention relates to an image reading and editing apparatus having a composite image forming function and particularly to a color image reading and editing apparatus to be used in association with a digital printer or an output memory device.
2. Description of the Prior Art
A conventional digital image processing apparatus for processing an image by digital data comprises an image reader for reading an image of an original and outputting digital data of the image, and a digital printer for printing an image based on the digital image data.
Such a conventional digital image processing apparatus is capable of easily performing various editing operations such as trimming or masking of an image, or composite image formation, since images are processed in the form of digital data.
Such a conventional digital image processing apparatus having the above described advantages performs image editing operations in the below described manner. For example, in order to compose two images separately trimmed from two originals, two image memories are provided. Then, digital data of the two image portions are stored in the respective image memories and a composite image is formed by transferring the data between the two memories. Thus, the two image memories each having a capacity for storing image data of an entire region of one page of the original are required in the above described conventional digital image processing apparatus. Consequently, the apparatus is not economical in view of the manufacturing cost as well as operation efficiency.
Under the circumstances, the assignee of the present invention proposed in Japanese Patent Application No. 61-24836, published as Japanese Kokai No. 62-181570, a monochrome image reader capable of editing images without requiring an image memory for storing image data of entire regions of two originals. This image reader has an attribute memory having a data region smaller than that of such an image memory. For example, attributes of an image for small sections such as bi-level or half-tone are stored in the data region. Various editing operations are performed in real time based on the attribute data. However, this monochrome image reader is not capable of composing more than two images.
A color image editing apparatus is disclosed in Japanese Patent Laying-Open Gazette (Kokai) No. 58-60875. In this apparatus, an area of an original is designated by a loop of a specified color and by reading the original, editing operations designated such as masking or transformation of black and red colors for the specified area and the area outside the specified area are performed. However, this apparatus is not capable of performing complicated editing operations such as editions different for each area. This apparatus is not capable of forming composite color images either.